Explosion building effects

This appendix is a summary of the woiit published in the so-called Green Book (1989). Possible effects of explosions on humans include blast-wave overpressure effects, explosion-wind effects, impact from fragments and debris, collapse of buildings, and heat-radiation effects. Heat-radiation effects ate not treated here see Chapter 6, Figure 6.10 and Table 6.6. 

Another safety issue to be considered which might be exacerbated in the reprocessing option is that the plutonium generated in power reactors, called reactor-grade plutonium because it is made up of a variety of plutonium isotopes, contains plutonium-241, which is subject to spontaneous fission (8). The mixture of isotopes makes it extremely difficult to build an effective nuclear weapon. However, an explosive device could be built using this mixture if control of detonation is sacrificed (48). 

EXP AC analyzes an interconnected network of building rooms and ventilation systems. A lumped-parameter formulation is used that includes the effects of inertial and choking flow in rapid gas transienl.s. The latest version is specifically suited to calculation of the detailed effects of explosions in the far field using a parametric representation of the explosive event. A material transport capability models the effects of convection, depletion, entrainment, and filtration of... 

This volume does not address subjects such as toxic effects, explosions in buildings and vessels, runaway reactions, condensed-phase explosions, pool fires, jet flames, or structural responses of buildings. Furthermore, no attempt is made to cover the frequency or likelihood that a related accident scenario will occur. References to other works are provided for readers interested in these phenomena. 

The nature of the hazard considering both intensity and duration. Shelters vary in tlic degree of protection provided. For tliermal tmd toxic hazards, shelters can liave a beneficial effect. However, for explosions, tlie hazard maybe greater because of the possibility of the building collapsing. 

A similar logic is applicable to the control of explosions involving gas or vapour, but other measures, e.g. dispersion by steam or containment by water curtains, may be applicable to vapour clouds in the open air. Containment or diversion of a blast (e.g. by blast walls) and reducing its effect by appropriate spacing of equipment, buildings etc. are also applicable. 

Distances are recommended for zoning of electrical equipment, separation of storage from buildings etc. Distances are also proposed (on the basis of experience) to minimize the escalation or effects on site of fire, explosion, toxic relea.se or similar incident. Selected sources of information are summarized in Table 11.6. A typical example is given in Table 11.8 subject to the requirement of Table 11.7. 

Segregation is practised to allow for housekeeping, construction and maintenance requirements and to reduce the risk of an accident resulting in a domino effect , e.g. from a fire, explosion or toxic release. For very toxic substances, e.g. prussic acid (HCN) or tetraethyl lead, this may involve isolating the entire manufacturing operation in a separate unoccupied building or sealed-off area. 

In a few, special situations, a building may need to be evaluated for the combined effects of explosion and toxic release. For example, in the event of an explosion, a building may retain sufficient structural integrity to protect the building occupants from the blast, yet suffer damage to the point that it can no longer offer sufficient protection from a toxic release occurring in conjunction with the explosion. 

Building evaluations must take into account the need for a cost-effective approach that allows facilities to focus resources on those buildings that present a significant risk to occupants, with assurances that all buildings that may be impacted by explosion or fire are appropriately considered. 

When handling flammable or combustible material, the resulting consequences could involve fire. Also, it is not uncommon for explosions involving flammable or combustible materials to be followed by fire, increasing the potential effects to building occupants. A detailed discussion on fire has not been included in this book because substantial literature is available on the effects of fire. Table 1.2 provides a number of references,... 

Other techniques that take into account some site-specific conditions, such as the Dow Fire and Explosion Index (Ref. 34) and the Mond Index (Ref. 39), have been used to prioritize buildings for evaluation. The results of these indices should be used in conjunction with consideration of other factors, rather than as stand-alone criteria. These other factors might include an evaluation of the effects of confinement and/or congestion-induced turbulence on the potential for blast. 

An explosion results in several structural loading effects, which can produce destmctive consequences to buildings and equipment. These consequences range from minor damage to complete collapse, depending on the structure s ability to withstand the loading effects. Table 5.1 summarizes the structural loadings that result from various explosion effects. 

Quantitative consequence evaluation requires determination of the blast overpressure and other explosion or fire effects that can impact a process plant building and a detailed analysis of the building s response. 

This section presents a brief description of the methods for determining the building response to explosions and how to interpret that response in terms of consequences to the building. Appendix B contains a general discussion on the principles of building design and evaluation for explosion effects. 

From the calculated building damage versus response relationship and the empirical probability of serious injury or fatality versus damage relationship discussed above, the relationship between explosion overpressure (or other effects) and probability of serious injury or fatality may be constructed in a manner that accounts for the detailed structural characteristics of plant buildings. The steps involved are similar to risk screening (Chapter 4), with the addition of detailed quantitative structural evaluation of plant buildings and detailed quantitative frequency assessment as described in the next section. 

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